Dust in workroom air of dental laboratories.

The general workroom air of eleven dental laboratories has been surveyed with respect to dust levels arising from cutting, grinding or polishing various dental materials like chromium-cobalt-, nickel- or gold alloys, amalgam and gypsum models, porcelain or denture base material. The materials were processed with cut or lathe wheels and various stones. The levels of the elements aluminium, calcium, cobalt, copper, chromium, gold, iron, lead, magnesium, manganese, nickel, silicon, silver, tin or titanium present in the collected dust samples did not exceed the respective threshold limit values. The dust was collected in workrooms with good general ventilation as well as in rooms with no use of ventilation systems. However, in breathing air close to workpiece, i.e. at distances of about 30 cm, threshold limit values for several elements or compounds could be considerably exceeded. The chemical analysis was accomplished by means of optical emission spectrography.